This invention relates to a novel process for the production of 3.alpha.-hydroxy-.DELTA..sup.9(11) -5.alpha.-20-ketopregnenes and their esters.
It is known from the works by Breslow et al., e.g., J. Amer. Chem. Soc. 96 (1974) 1973; ibid. 96 (1974) 6791, that it is possible, in case of steroids esterified in the 3.alpha.-position, to chlorinate the tertiary C.sub.5, C.sub.9 and C.sub.14 carbon atoms with dichloroiodobenzene under the influence of light and then split off hydrogen chloride again with the formation of a double bond at these positions.
However, this process has the disadvantage that it is applicable solely to those steroids which have no free carbonyl groups, such as 20-ketopregnanes.
In the process of this invention, 9.alpha.-chloro-20-ketopregnanes are selectively produced from which hydrogen chloride is subsequently split off with a silver salt in a conventional manner to form a .DELTA..sup.9(11) -double bond.